Underground bores such as oil wells, pipelines, gas mains and the like are susceptible to cracking or rupturing due to corrosion of the existing casings, shifts in the ground and external pressures which can crush or rupture the bores. These losses of integrity can cause the fluids passing through them to seep into the environment which can cause contamination to water tables as well as presenting fire hazards in the cases of gas mains and the like.
Likewise, certain situations require the closure of previous perforations or other man-made openings in casings, tubings or the like. In some cases repairs are required to bores that have been damaged by wear or abrasion by moving components. Also, the relining of a bore to present a different material interface within the bore can be extremely advantageous.
To repair these bores various elaborate methods have been developed which generally involve inserting a new section of pipe or liner into the bore to be repaired and placing the new lining in the appropriate section and then expanding the lining so that it then fills or covers the gap. These methods for repairing the casings generally have been limited to fairly small areas because of the difficulties encountered in handling long liners, and have largely been unsuccessful due to the problem of "springback" of metallic tubular materials when expanded internally. Springback prevents establishment of a good seal against the well casing.